as far as quality goes tiff is probably the best or maybe bmp because there is no quality lost from the scan. jpg provides great compression rates, but with some quality degredation. for the web this quality loss is generally not a problem due to image sizes and screen resolution. if you are going to blow up the images or print them out you may want to stick with a lossless format such as tiff or bmp. with tiff you can also compress the file using a built in lossles algorythm, which can greatly reduce file sizes, athough generally not as much as jpeg. gif is pretty bad for photos.
A lossless format which is not really common but is actually very good is the .PNG format. This format was supposed to replace the .GIF format which can only use 256 colors maximum and has a pretty good compression too (but lossless as I already said). It's also compatible with the major internet browsers, which means you can insert .PNG files in web pages without problems.
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